/*
 * @(#)ExampleFileFilter.java	1.16 04/07/26
 * 
 * Copyright (c) 2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduce the above copyright notice, 
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL 
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST 
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, 
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY 
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, 
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

package orbisoftware.ddstools.sessionplayer;

/*
 * @(#)ExampleFileFilter.java	1.16 04/07/26
 */

import java.io.File;
import java.util.Hashtable;
import java.util.Enumeration;
import javax.swing.filechooser.*;

/**
 * A convenience implementation of FileFilter that filters out all files except
 * for those type extensions that it knows about.
 * 
 * Extensions are of the type ".foo", which is typically found on Windows and
 * Unix boxes, but not on Macinthosh. Case is ignored.
 * 
 * Example - create a new filter that filerts out all files but gif and jpg
 * image files:
 * 
 * JFileChooser chooser = new JFileChooser(); ExampleFileFilter filter = new
 * ExampleFileFilter( new String{"gif", "jpg"}, "JPEG & GIF Images")
 * chooser.addChoosableFileFilter(filter); chooser.showOpenDialog(this);
 * 
 * @version 1.16 07/26/04
 * @author Jeff Dinkins
 */
public class FileExtensionFilter extends FileFilter {

   private Hashtable<Object, FileExtensionFilter> filters = null;
   private String description = null;
   private String fullDescription = null;
   private boolean useExtensionsInDescription = true;

   /**
    * Creates a file filter. If no filters are added, then all files are
    * accepted.
    * 
    * @see #addExtension
    */
   public FileExtensionFilter() {
      this.filters = new Hashtable<Object, FileExtensionFilter>();
   }

   /**
    * Creates a file filter that accepts files with the given extension.
    * Example: new ExampleFileFilter("jpg");
    * 
    * @see #addExtension
    */
   public FileExtensionFilter(String extension) {
      this(extension, null);
   }

   /**
    * Creates a file filter that accepts the given file type. Example: new
    * ExampleFileFilter("jpg", "JPEG Image Images");
    * 
    * Note that the "." before the extension is not needed. If provided, it will
    * be ignored.
    * 
    * @see #addExtension
    */
   public FileExtensionFilter(String extension, String description) {
      this();
      if (extension != null)
         addExtension(extension);
      if (description != null)
         setDescription(description);
   }

   /**
    * Creates a file filter from the given string array. Example: new
    * ExampleFileFilter(String {"gif", "jpg"});
    * 
    * Note that the "." before the extension is not needed adn will be ignored.
    * 
    * @see #addExtension
    */
   public FileExtensionFilter(String[] filters) {
      this(filters, null);
   }

   /**
    * Creates a file filter from the given string array and description.
    * Example: new ExampleFileFilter(String {"gif", "jpg"},
    * "Gif and JPG Images");
    * 
    * Note that the "." before the extension is not needed and will be ignored.
    * 
    * @see #addExtension
    */
   public FileExtensionFilter(String[] filters, String description) {
      this();
      for (int i = 0; i < filters.length; i++) {
         // add filters one by one
         addExtension(filters[i]);
      }
      if (description != null)
         setDescription(description);
   }

   /**
    * Return true if this file should be shown in the directory pane, false if
    * it shouldn't.
    * 
    * Files that begin with "." are ignored.
    * 
    * @see #getExtension
    * @see FileFilter#accepts
    */
   public boolean accept(File f) {
      if (f != null) {
         if (f.isDirectory()) {
            return true;
         }
         String extension = getExtension(f);
         if (extension != null && filters.get(getExtension(f)) != null) {
            return true;
         }
         ;
      }
      return false;
   }

   /**
    * Return the extension portion of the file's name .
    * 
    * @see #getExtension
    * @see FileFilter#accept
    */
   public String getExtension(File f) {
      if (f != null) {
         String filename = f.getName();
         int i = filename.lastIndexOf('.');
         if (i > 0 && i < filename.length() - 1) {
            return filename.substring(i + 1).toLowerCase();
         }
         ;
      }
      return null;
   }

   /**
    * Adds a filetype "dot" extension to filter against.
    * 
    * For example: the following code will create a filter that filters out all
    * files except those that end in ".jpg" and ".tif":
    * 
    * ExampleFileFilter filter = new ExampleFileFilter();
    * filter.addExtension("jpg"); filter.addExtension("tif");
    * 
    * Note that the "." before the extension is not needed and will be ignored.
    */
   public void addExtension(String extension) {
      if (filters == null) {
         filters = new Hashtable<Object, FileExtensionFilter>(5);
      }
      filters.put(extension.toLowerCase(), this);
      fullDescription = null;
   }

   /**
    * Returns the human readable description of this filter. For example:
    * "JPEG and GIF Image Files (*.jpg, *.gif)"
    * 
    * @see setDescription
    * @see setExtensionListInDescription
    * @see isExtensionListInDescription
    * @see FileFilter#getDescription
    */
   public String getDescription() {
      if (fullDescription == null) {
         if (description == null || isExtensionListInDescription()) {
            fullDescription = description == null ? "(" : description + " (";
            // build the description from the extension list
            Enumeration<Object> extensions = filters.keys();
            if (extensions != null) {
               fullDescription += "." + (String) extensions.nextElement();
               while (extensions.hasMoreElements()) {
                  fullDescription += ", ." + (String) extensions.nextElement();
               }
            }
            fullDescription += ")";
         } else {
            fullDescription = description;
         }
      }
      return fullDescription;
   }

   /**
    * Sets the human readable description of this filter. For example:
    * filter.setDescription("Gif and JPG Images");
    * 
    * @see setDescription
    * @see setExtensionListInDescription
    * @see isExtensionListInDescription
    */
   public void setDescription(String description) {
      this.description = description;
      fullDescription = null;
   }

   /**
    * Determines whether the extension list (.jpg, .gif, etc) should show up in
    * the human readable description.
    * 
    * Only relevant if a description was provided in the constructor or using
    * setDescription();
    * 
    * @see getDescription
    * @see setDescription
    * @see isExtensionListInDescription
    */
   public void setExtensionListInDescription(boolean b) {
      useExtensionsInDescription = b;
      fullDescription = null;
   }

   /**
    * Returns whether the extension list (.jpg, .gif, etc) should show up in the
    * human readable description.
    * 
    * Only relevant if a description was provided in the constructor or using
    * setDescription();
    * 
    * @see getDescription
    * @see setDescription
    * @see setExtensionListInDescription
    */
   public boolean isExtensionListInDescription() {
      return useExtensionsInDescription;
   }
}
